Acoustic Touch Sensitive Testing

ABSTRACT

Acoustic touch sensitive testing techniques are described. In one or more implementations, a touch-sensitive surface of a touch-sensitive device is tested by detecting contact made with the touch sensitive surface using an acoustic sensor and comparing data describing the contact that is received from the acoustic sensor with data describing the contact that is received from the touch-sensitive device.

BACKGROUND

Display and input techniques utilized by computing devices are ever evolving. For example, initial computing devices were provided with monitors. A user interacted with the computing device by viewing simple text on the monochrome monitor and entering text via a keyboard that could then be viewed on the monitor. Other techniques were then subsequently developed, such as graphical user interfaces and cursor control devices.

Display and input techniques have continued to evolve, such as to sense touch using a touchscreen display of a computing device to recognize gestures. A user, for instance, may interact with a graphical user interface by inputting a gesture using the user's hand that is detected by the touchscreen display or other touch-sensitive device. However, traditional techniques that were utilized to test touchscreen displays and other touch-sensitive devices were often inaccurate and therefore were typically inadequate to test the touchscreen displays as suitable for intended use of the device.

SUMMARY

Acoustic touch sensitive testing techniques are described. In one or more implementations, a touch-sensitive surface of a touch-sensitive device is tested by detecting contact made with the touch sensitive surface using an acoustic sensor and comparing data describing the contact that is received from the acoustic sensor with data describing the contact that is received from the touch-sensitive device.

In one or more implementations, an apparatus includes an acoustic sensor configured for placement proximal a touch-sensitive surface and one or more modules implemented at least partially in hardware to use a signal received from the acoustic sensor and a signal received from the touch-sensitive surface to test the touch-sensitive surface.

In one or more implementations, a system includes one or more modules that are implemented at least partially in hardware and configured to test latency of a touchscreen of a touchscreen device using a signal received from an acoustic sensor that is disposed proximal to a touchscreen of the touchscreen device to detect contact made with the touchscreen and data received from the touchscreen device that describes the contact.

This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description is described with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The use of the same reference numbers in different instances in the description and the figures may indicate similar or identical items.

FIG. 1 is an illustration of an environment in an example implementation that is operable to utilize acoustic testing techniques described herein.

FIG. 2 is an illustration of a system in an example implementation showing a test apparatus of FIG. 1 in greater detail.

FIG. 3 depicts a graph showing an electrical voltage drop on a resistor as being used as a reference as to when contact occurred.

FIG. 4 depicts a graph showing latency induced by physical processes producing a sound wave as defined as a difference between a moment the signal from acoustic wave crosses a predefined threshold and a moment a voltage drop occurred.

FIG. 5 depicts a graph as showing an example measurement taken using an oscilloscope.

FIG. 6 depicts a system in an example implementation showing a measuring setup for detection of touch event time via software post processing.

FIG. 7 is a flow diagram depicting a procedure in an example implementation in which an acoustic testing technique is described.

FIG. 8 illustrates various components of an example device that can be implemented as any type of computing device as described with reference to FIGS. 1, 2 and 6 to implement embodiments of the techniques described herein.

DETAILED DESCRIPTION

Overview

Conventional techniques that were utilized to test touchscreens and other touch-sensitive devices were often difficult to reproduce. Consequently, test results from these conventional techniques could be inaccurate and difficult to interpret and thus often failed for their intended purpose.

Acoustic touch sensitive testing techniques are described herein. In one or more implementations, techniques are described in which acoustic techniques are utilized to test a touch-sensitive device, such as a touchscreen. For example, an acoustic sensor may be used to detect “when” contact is made with a touchscreen of a touchscreen device. The input detected using the acoustic sensor may then be compared with an input generated by the touchscreen device to test functionality of the touchscreen device, such as to determine latency. Further discussion of these and other testing techniques may be found in relation to the following sections.

In the following discussion, an example environment is first described that may employ the testing techniques described herein in relation to a touchscreen device. However, it should be readily apparent that a variety of touch sensitive devices are also contemplated, such as track pads and other sensing devices. Example procedures are then described which may be performed in the example environment as well as other environments. Consequently, performance of the example procedures is not limited to the example environment and the example environment is not limited to performance of the example procedures.

Example Environment

FIG. 1 depicts an environment 100 in an example implementation that includes a test apparatus 102 that is suitable to test a touchscreen device 104. The touchscreen device 104 may be configured in a variety of ways. For example, the touchscreen device 104 may be configured as part of a mobile communication device such as a mobile phone, a portable game-playing device, a tablet computer, as part of a traditional computing device (e.g., a display device that is part of a laptop or personal computer), and so on.

Additionally, the touchscreen 106 of the touchscreen device 104 may be configured in a variety of ways. For example, the touchscreen 106 of the touchscreen device 104 may include sensors that are configured to detect proximity (e.g., contact) with the touchscreen 106. Touch sensors 110 are typically used to report actual contact with the touchscreen 106, such as when being touched with a finger of a user's hand 108.

Examples of such touch sensors 110 include capacitive touch sensors. For instance, in projected capacitance an X-Y grid may be formed across the touchscreen using near optically transparent conductors (e.g., indium tin oxide) to detect contact at different X-Y locations on the touchscreen 106. Other capacitance techniques are also contemplated, such as surface capacitance, mutual capacitance, self-capacitance, and so on. Further, other touch sensors 110 are also contemplated in other instances, such as infrared, optical imaging, dispersive signal technology, acoustic pulse recognition, and so on.

Regardless of the type of touch sensors 110 used, inputs detected by the touch sensors 110 may then be processed by the touch module 112 to detect characteristics of the inputs, which may be used for a variety of purposes. For example, the touch module 112 may recognize that the touch input indicates selection of a particular object, may recognize one or more inputs as a gesture usable to initiate an operation of the touchscreen device 104 (e.g., expand a user interface), and so forth. However, this processing may rely upon the accuracy of the inputs and therefore conventional techniques that were utilized to test the touchscreen 106 could result in an inaccurate touchscreen making it to market, which could hinder a user's interaction with the device.

In one or more implementations described herein, an ability of a touchscreen 106 to detect contact (e.g., by a finger of a user's hand 108) is tested by the test apparatus 102. For example, the test apparatus 102 may include a test module 114 and acoustic sensor 116. The acoustic sensor 116 may be utilized to test the touchscreen device 104 in a variety of ways. For instance, the test module 114 may leverage the acoustic sensor 116 to measure response latency the touchscreen device 104, such as an ability of the touch module 112 to detect contact by one or more fingers of the user's hand 108 (or other objects) with the touchscreen 106. This may be performed in a variety of ways, an example of which may be found in relation to FIG. 2.

Generally, any of the functions described herein can be implemented using software, firmware, hardware (e.g., fixed logic circuitry), or a combination of these implementations. The terms “module,” “functionality,” and “logic” as used herein generally represent software, firmware, hardware, or a combination thereof. In the case of a software implementation, the module, functionality, or logic represents program code that performs specified tasks when executed on a processor (e.g., CPU or CPUs). The program code can be stored in one or more computer readable memory devices. The features of the techniques described below are platform-independent, meaning that the techniques may be implemented on a variety of commercial computing platforms having a variety of processors.

For example, the test apparatus 102 and/or the touchscreen device 104 may be implemented using a computing device. The computing device may also include an entity (e.g., software) that causes hardware of the computing device to perform operations, e.g., processors, functional blocks, a “system-on-a-chip,” and so on. For example, the computing device may include a computer-readable medium that may be configured to maintain instructions that cause the computing device, and more particularly hardware of the computing device to perform operations. Thus, the instructions function to configure the hardware to perform the operations and in this way result in transformation of the hardware to perform functions. The instructions may be provided by the computer-readable medium to the computing device through a variety of different configurations.

One such configuration of a computer-readable medium is signal bearing medium and thus is configured to transmit the instructions (e.g., as a carrier wave) to the hardware of the computing device, such as via a network. The computer-readable medium may also be configured as a computer-readable storage medium and thus is not a signal bearing medium. Examples of a computer-readable storage medium include a random-access memory (RAM), read-only memory (ROM), an optical disc, flash memory, hard disk memory, and other memory devices that may use magnetic, optical, and other techniques to store instructions and other data.

FIG. 2 is an illustration of a system 200 in an example implementation showing the test apparatus 102 of FIG. 1 in greater detail. The test apparatus 102 in this example is configured to leverage acoustic wave detection to evaluate latency of a touch-sensitive device, such as the touchscreen 106 of the touchscreen device 104. The test module 114, for instance, may be configured to detect a sound wave produced when contact 202 is made with a surface, e.g., the touchscreen 106 in this example, which may be used to define a moment at which physical touch has occurred.

Processing of one or more contacts by a touchscreen device 104 may involve the following. First, physical contact 202 is detected by one or more touch sensors 110 of the touchscreen device 104, resulting in an electrical signal The electrical signal is then processed by the touch module 112 to determine “what” the signal describes, e.g., characteristics of the contact 202 such as where the contact occurred. This processing may then be reported to the test module 114 as a system touch event time 204 (Ts) 204 for testing purposes. Thus, detection and processing of the contact 202 may take time to complete, which may therefore be thought of as latency of the touchscreen device 104 in detecting the contact 202.

In order to test latency, the test module 114 may employ one or more acoustic sensors 116 (e.g., a piezo-transducer) that are positioned at or near the touch-sensitive surface, e.g., the touchscreen 106. A signal from the acoustic sensors 116 may then be amplified by an amplifier 206 and processed by a touch detection module 208 to determine an acoustic touch event time (Ta) 210. This processing, for instance, may include identification of an actual signal from background noise detected by the acoustic sensors 116. A latency evaluation module 212 may then determine a time associated with a touch event, e.g., the moment of contact. This may be determined by detecting a difference in the amount of time between the system touch event time 204 and the acoustic touch event time 210.

As should be readily apparent, operation of the test apparatus 102 may also involve latency. This may include duration and latency of the physical process occurring during interaction of the touching object with the touch sensitive surface which produces acoustic waves, speed of the propagation of the acoustic waves on that surface, distance between touch point and acoustic sensor, latency in producing electrical signal in the electronic acoustic detector, and latency of an electronic registration system used to store results of the latency evaluation module 212. However, this latency is generally below one millisecond.

For example, production of an acoustic vibration on the touch surface from the contact 202 is generally between 30 and 100 uS in case of hard surface as a glass or wood and depends on the speed of the contact. As the speed of sound on a solid surface is in the order of over a thousand of meters per second, the time taken for the acoustic vibrations to reach the sensor may be within few hundreds microseconds when the acoustic sensor 116 is positioned within few centimeters from the point of contact 202. Hence, if a piezo-transducer is used as acoustic detector, then the time used to produce an electrical signal from acoustic vibrations may be below one microsecond. The amount of time consumed by the touch detection module 208 to identify the contact 202 that produced acoustic signal from the background noise may be dependent on a level of that noise, frequency and magnitude of the touch event signal, and so on.

In an implementation example, the system 200 may be configured as follows. In order to produce the contact 202, a thin conductive plate may be positioned on the surface of the touch-sensitive surface to be tested to act as the contact 202. The conductive plate and the human body are connected to an electrical circuit so that when the finger touches the plate and electrical current flows through the finger and plate. The electrical current is amplified and a voltage drop on a resistor is measured in order to detect the moment and dynamics of the contact 202. Although use of a user is described, this process may also be automated using non-human motion.

An acoustic sensor 116 is positioned close to the conductive plate. A signal from the acoustic sensor 116 is amplified and recorded by the test module 114 as described earlier. An electrical voltage drop on the resistor is then used as reference to when the actual touch contact occurred, an example of which is shown in the graph 300 of FIG. 3.

Latency induced by physical processes producing sound wave is defined as difference between the moment the signal from acoustic wave crosses a predefined threshold and the moment the voltage drop occurred as shown by the graph 400 of FIG. 4. The threshold, for instance, may be defined to be greater than a maximum magnitude of the existing background noise.

An example measurement as may be taken using an oscilloscope is shown in the example graph 500 of FIG. 5. Since triggering may occur either during first or second phase of the acoustic signal, the signal may be passed through a rectifier to convert the original signal into single polarity to minimize error in latency evaluation. Comparison with the predefined threshold may be made in real time using hardware and/or via software post processing. Electronic comparison with the threshold can be accomplish by using analog comparator or using digital comparator after digitizing the signal and comparing it digitally with the threshold value.

FIG. 6 depicts a system 600 in an example implementation showing a measuring setup for detection of touch event time via software post processing. In this example, a system under test 602 (e.g., the touchscreen device 104) is tested by the test apparatus 102 based on a recorded signal.

The test module 114, for instance, may include a recorder 604 to continuously record a signal from the acoustic sensor 116. The recording may be set to last for at least a duration that is greater than expected or known latency of the system under test 602.

Upon receiving a system touch event 606 from the system under test 602, the latency evaluation module 212 may send a stop recording 608 signal to the recorder 604. In response to that signal, the recorder 604 may stop recording and send back the recorded signal 610 to the latency evaluation module 212. The latency evaluation module 212 may then process the data and identify a first moment of time, at which, the recorded acoustic signal has crossed the threshold value as shown in the graphs. Further discussion of acoustic touch sensitive testing may be found in relation to the following procedures.

Although a single acoustic sensor 116 was described above, a plurality of acoustic sensor may be utilized. For example, a plurality of acoustic sensors 116 may be used to perform trilateration to estimate a position of a contact and thus enable an estimation of an amount of time consumed for a wave to reach the acoustic sensors 116. This may be used to provide a better estimate for latency, and hence improve the process. A variety of other examples are also contemplated, such as to employ feedback from both acoustic sensors 116 (e.g., averaging) for processing.

Example Procedures

The following discussion describes touchscreen testing techniques that may be implemented utilizing the previously described systems and devices. Aspects of each of the procedures may be implemented in hardware, firmware, or software, or a combination thereof. The procedures are shown as a set of blocks that specify operations performed by one or more devices and are not necessarily limited to the orders shown for performing the operations by the respective blocks. In portions of the following discussion, reference will be made to the environment 100 of FIG. 1, the systems 200, 600 of FIGS. 2 and 6, and the graphs 300-500 of FIGS. 3-5.

FIG. 7 is a flow diagram depicting a procedure 900 in an example implementation in which a touch-sensitive surface is tested using acoustic techniques. A touch-sensitive surface of a touch-sensitive device is tested (block 702) by detecting contact made with the touch sensitive surface using an acoustic sensor (block 704). As previously described, the touch-sensitive surface may be configured in a variety of ways, such as a touchscreen device, track pad, and so on. Thus, the touch-sensitive surface may employ a variety of techniques to detect contact, such as capacitive, imaging (e.g., IR, cameras, and so on), and so forth.

Data describing the contact that is received from the acoustic sensor with data describing the contact that is received from the touch-sensitive device (block 706). A test module 114 may employ a variety of different techniques to test a touch-sensitive surface. As shown in FIGS. 2 and 6, for instance, a latency evaluation module 212 may be employed to detect latency in an ability of a touchscreen device 104 to recognize contact. A variety of other examples are also contemplated.

Example Device

FIG. 8 illustrates various components of an example device 800 that can be implemented as any type of computing device as described with reference to FIGS. 1, 2, and 6 to implement embodiments of the techniques described herein. Device 800 includes communication devices 802 that enable wired and/or wireless communication of device data 804 (e.g., received data, data that is being received, data scheduled for broadcast, data packets of the data, etc.). The device data 804 or other device content can include configuration settings of the device, media content stored on the device, and/or information associated with a user of the device. Media content stored on device 800 can include any type of audio, video, and/or image data. Device 800 includes one or more data inputs 806 via which any type of data, media content, and/or inputs can be received, such as user-selectable inputs, messages, music, television media content, recorded video content, and any other type of audio, video, and/or image data received from any content and/or data source.

Device 800 also includes communication interfaces 808 that can be implemented as any one or more of a serial and/or parallel interface, a wireless interface, any type of network interface, a modem, and as any other type of communication interface. The communication interfaces 808 provide a connection and/or communication links between device 800 and a communication network by which other electronic, computing, and communication devices communicate data with device 800.

Device 800 includes one or more processors 810 (e.g., any of microprocessors, controllers, and the like) which process various computer-executable instructions to control the operation of device 800 and to implement embodiments of the techniques described herein. Alternatively or in addition, device 800 can be implemented with any one or combination of hardware, firmware, or fixed logic circuitry that is implemented in connection with processing and control circuits which are generally identified at 812. Although not shown, device 800 can include a system bus or data transfer system that couples the various components within the device. A system bus can include any one or combination of different bus structures, such as a memory bus or memory controller, a peripheral bus, a universal serial bus, and/or a processor or local bus that utilizes any of a variety of bus architectures.

Device 800 also includes computer-readable media 814, such as one or more memory components, examples of which include random access memory (RAM), non-volatile memory (e.g., any one or more of a read-only memory (ROM), flash memory, EPROM, EEPROM, etc.), and a disk storage device. A disk storage device may be implemented as any type of magnetic or optical storage device, such as a hard disk drive, a recordable and/or rewriteable compact disc (CD), any type of a digital versatile disc (DVD), and the like. Device 800 can also include a mass storage media device 816.

Computer-readable media 814 provides data storage mechanisms to store the device data 804, as well as various device applications 818 and any other types of information and/or data related to operational aspects of device 800. For example, an operating system 820 can be maintained as a computer application with the computer-readable media 814 and executed on processors 810. The device applications 818 can include a device manager (e.g., a control application, software application, signal processing and control module, code that is native to a particular device, a hardware abstraction layer for a particular device, etc.). The device applications 818 also include any system components or modules to implement embodiments of the techniques described herein. In this example, the device applications 818 include an interface application 822 and an input/output module 824 (which may be the same or different as input/output module 84) that are shown as software modules and/or computer applications. The input/output module 824 is representative of software that is used to provide an interface with a device configured to capture inputs, such as a touchscreen, track pad, camera, microphone, and so on. Alternatively or in addition, the interface application 822 and the input/output module 824 can be implemented as hardware, software, firmware, or any combination thereof. Additionally, the input/output module 824 may be configured to support multiple input devices, such as separate devices to capture visual and audio inputs, respectively.

Device 800 also includes an audio and/or video input-output system 826 that provides audio data to an audio system 828 and/or provides video data to a display system 830. The audio system 828 and/or the display system 830 can include any devices that process, display, and/or otherwise render audio, video, and image data. Video signals and audio signals can be communicated from device 800 to an audio device and/or to a display device via an RF (radio frequency) link, S-video link, composite video link, component video link, DVI (digital video interface), analog audio connection, or other similar communication link. In an embodiment, the audio system 828 and/or the display system 830 are implemented as external components to device 800. Alternatively, the audio system 828 and/or the display system 830 are implemented as integrated components of example device 800.

CONCLUSION

Although the invention has been described in language specific to structural features and/or methodological acts, it is to be understood that the invention defined in the appended claims is not necessarily limited to the specific features or acts described. Rather, the specific features and acts are disclosed as example forms of implementing the claimed invention. 

What is claimed is:
 1. A method implemented by one or more devices, the method comprising: testing a touch-sensitive surface of a touch-sensitive device by: detecting contact made with the touch-sensitive surface using an acoustic sensor; and comparing data describing the contact that is received from the acoustic sensor with data describing the contact that is received from the touch-sensitive device.
 2. A method as described in claim 1, wherein the testing is configured to determine latency of detection of the contact by the touch-sensitive device.
 3. A method as described in claim 1, wherein the detecting is performed using the acoustic sensor by detecting when a signal from the acoustic sensor passes a defined threshold.
 4. A method as described in claim 3, wherein the threshold is defined to correspond to an approximate maximum magnitude associated with background noise.
 5. A method as described in claim 1, wherein the detecting includes converting a signal received from the acoustic sensor to a single polarity.
 6. A method as described in claim 5, wherein the converting is performed by passing the signal through a rectifier.
 7. A method as described in claim 1, wherein the detecting includes use of a recorder that is configured to record a signal from the acoustic sensor and the comparing includes use of software post processing.
 8. A method as described in claim 1, wherein the touch-sensitive surface is a touchscreen.
 9. A method as described in claim 8, wherein the touchscreen employs one or more capacitive sensors to detect the contact.
 10. A method as described in claim 9, wherein the contact is grounded to be detectable by the one or more capacitive sensors.
 11. A method as described in claim 8, wherein the touchscreen is operable as a display for a mobile communications device.
 12. A method as described in claim 1, wherein the contact is made by a human user.
 13. A method as described in claim 1 wherein the detecting is performed by a plurality of said acoustic sensors.
 14. A method as described in claim 1, further comprising performing trilateration using signals obtained from a plurality of said acoustic sensors to estimate a position of the contact.
 15. An apparatus comprising: an acoustic sensor configured for placement proximal a touch-sensitive surface; and one or more modules implemented at least partially in hardware to use a signal received from the acoustic sensor and a signal received from the touch-sensitive surface to test the touch-sensitive surface.
 16. An apparatus as described in claim 15, wherein the one or more modules are configured to test latency in an ability of a device that employs the touch-sensitive surface to detect contact.
 17. An apparatus as described in claim 15, wherein the one or more modules are configured to test the touch-sensitive surface by comparing the signal received from the acoustic sensor and the signal received from the touch-sensitive surface.
 18. An apparatus as described in claim 15, wherein the acoustic sensor is configured to detect an acoustic wave produced by contact with the touch-sensitive surface.
 19. A system comprising one or more modules that are implemented at least partially in hardware and configured to test latency of a touchscreen of a touchscreen device using a signal received from an acoustic sensor that is disposed proximal to a touchscreen of the touchscreen device to detect contact made with the touchscreen and data received from the touchscreen device that describes the contact.
 20. A system as described in claim 19, wherein the touchscreen device is configured as a mobile phone. 